Integrated antenna arrays for wireless power transmission

ABSTRACT

A plurality of integrated antenna structures may be formed in flat panel antenna arrays which may be arranged in equally spaced grid and may be used in transmitters for sending focused RF waves towards a receiver for wireless power charging or powering. Each of the integrated antenna structures may include PIFAs integrated with AMC metamaterials. As a result of their high directionality and form factor, the integrated antenna structures may be placed very close together, thus enabling the integration of a high number of integrated antenna structures in a single flat panel antenna array which may fit about 400+ integrated antenna structures. Each integrated antenna structure in the flat panel antenna arrays may be operated independently, thus enabling an enhanced control over the pocket forming. In addition, the higher number of integrated antenna structures may contribute to a higher gain for the flat panel antenna arrays.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent application Ser. No. 14/336,963, filed on Jul. 21, 2014, which is herein fully incorporated by reference in its entirety.

This application relates to U.S. Non-Provisional patent application Ser. No. 14/583,625, filed Dec. 27, 2014, entitled “Receivers for Wireless Power Transmission,” U.S. Non-Provisional patent application Ser. No. 14/583,630, filed Dec. 27, 2014, entitled “Methodology for Pocket-Forming,” U.S. Non-Provisional patent application Ser. No. 14/583,634, filed Dec. 27, 2014, entitled “Transmitters for Wireless Power Transmission,” U.S. Non-Provisional patent application Ser. No. 14/583,640, filed Dec. 27, 2014, entitled “Methodology for Multiple Pocket-Forming,” U.S. Non-Provisional patent application Ser. No. 14/583,641, filed Dec. 27, 2014, entitled “Wireless Power Transmission with Selective Range,” U.S. Non-Provisional patent application Ser. No. 14/583,643, filed Dec. 27, 2014, entitled “Method for 3 Dimensional Pocket-Forming,” all of which are incorporated herein by reference in their entirety.

TECHNICAL FIELD

The present disclosure relates in general to antennas, and more specifically, to compact and directional antenna arrays that may include a plurality of integrated antenna structures for wireless power transmission.

BACKGROUND

Wireless power transmission may include a transmitter for forming and directing radio frequency (RF) waves towards a receiver which may convert RF waves into usable power for charging or powering an electronic device. The receiver may be integrated in the electronic device (e.g., a smartphone, a tablet) or may be in the form of cases that may be operatively coupled with the electronic device for suitable charging or powering. The transmitter may include an antenna array composed of a plurality of directional antennas.

The antenna arrays may be controlled by computer hardware and software in order to broadcast a wireless signal towards the receiver. Amplitude and phase among other properties of the transmitted RF waves may be tuned by the computer hardware and software to form constructive and destructive interference patterns generating pockets of energy in a 3-dimensional shape from the constructive patterns, and null spaces from the destructive patterns to aim the pockets of energy to specific receivers.

The number of antennas in the antenna arrays may vary in relation with the desired power range and transmission capability of the transmitter. The more antennas in the array, the wider the range and higher the power transmission potential available at the transmitter. More antennas may additionally enable the transmitter to target more receivers at once. Directional antenna designs that can be integrated in transmitters may include Yagi, log-periodic, corner reflectors, and parabolic antennas, among others.

However, size may be one important factor that may impact the number of antennas that can be integrated in the antenna arrays for the transmitter. Designers often look for the optimal combination of size and performance in the antennas integrated in the transmitter, where the performance is usually hampered when size is reduced.

Planar inverted-F antennas (PIFA) may be fabricated in small form factors that may allow for dense antenna arrays. However, PIFA antenna's radiation pattern is commonly omnidirectional, and as a result, it may waste transmitted power if included in the transmitter. Additionally, the omnidirectional radiation patterns may hinder the transmitter ability to focus the transmitted RF waves to specific receivers.

Although other antennas designs may provide significant gain, arrays of independently fed antennas may provide a transmitter with flexibility of control. Flexible control may allow for the formation of highly directional lobes and pocket forming which may lead to more efficiency obtained from the antenna arrays.

For the foregoing reasons, there is a need for a plurality of directional antennas that could be formed on arrays of reasonably small size while keeping a suitable performance, and that could be controlled and fed independently on the arrays.

SUMMARY

The present disclosure may describe a plurality of integrated antenna structures formed on a flat panel antenna arrays. Specifically, integrated antenna structures may include a PIFA integrated with artificial magnetic conductors (AMC) metamaterials formed on multi-layer printed circuit board (PCB).

The PIFA described herein may include an antenna element with two or more slots formed over the top layer of a four layer PCB, where these antenna slots may be designed for reducing the area of the antenna while keeping a suitable impedance bandwidth. In addition, PIFA configurations may also include a ground element formed on the bottom layer of the PCB and operatively coupled with the antenna element through ground and signal vias. The ground element may also have a large part of its central area missing. PIFA configuration may also include a folded ground formed over the empty space of a PCB top layer, without interfering with the operation of an antenna element which may be also formed over the PCB top layer.

One exemplary embodiment of the present disclosure may include the integration of a PIFA with a first AMC metamaterial to form a first integrated antenna structure. The first AMC metamaterial may be formed with 5×5 arrays of AMC unit cells, where each AMC unit cell may include an AMC metal layer that may exhibit a square θ ring shape and a backing metal layer. The first AMC metamaterial may be formed over a large multi-layer and monolithic PCB that may fit a plurality of AMC unit cells.

Another exemplary embodiment of the present disclosure may include the integration of a PIFA (same as described above) with a second AMC metamaterial to form a second integrated antenna structure. Specifically, the second AMC metamaterial embodiment may be formed with 6×6 arrays of AMC unit cells, where each AMC unit cell may include an AMC metal layer which may exhibit a square shape, and a backing metal layer. The second AMC metamaterial may be formed over a large multi-layer and monolithic PCB that may fit a plurality of AMC unit cells.

According to embodiments described herein, flat panel antenna arrays may include an N number of the first or second integrated antenna structures which may be distributed in an equally spaced grid and may be fed independently. The compact dimensions and high directivity exhibited by the first or second integrated antenna structures may allow the integration of a higher number of antennas in the flat panel antenna arrays while allowing for an enhanced control over pocket forming.

In other embodiments, flat panel antenna arrays may include one or more first or second integrated antenna structures operatively connected to one or more RFIC. The RFIC may include a proprietary chip for adjusting phases and/or relative magnitudes of RF signals which may serve as inputs for the integrated antenna structures for controlling pocket-forming. A single RFIC may control one, two, four or more integrated antenna structures configured in rows or columns, or any other arrangements.

The compact dimensions and high directivity of the integrated antenna structures may allow them to be placed closer to each other in the flat panel antenna arrays, thereby contributing to the fabrication of compact transmitters for wireless power transmission. In addition, by independently feeding each of the integrated antenna structures in the flat panel antenna arrays, a higher control over pocket forming may be achieved.

Numerous other aspects, features and benefits of the present disclosure may be made apparent from the following detailed description taken together with the drawing figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure can be better understood by referring to the following figures. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the disclosure. In the figures, reference numerals designate corresponding parts throughout the different views.

FIG. 1 illustrates a wireless power transmission example situation using pocket-forming.

FIG. 2 illustrates a component level embodiment for a transmitter.

FIG. 3 illustrates an isometric view of an exemplary first integrated antenna structure, according to an embodiment.

FIG. 4A illustrates a top view of an exemplary first integrated antenna structure, according to an embodiment.

FIG. 4B illustrates a side view of an exemplary first integrated antenna structure, according to the embodiment.

FIG. 5A illustrates the impedance bandwidth response of a first integrated antenna structure, according to an embodiment.

FIG. 5B illustrates a radiation pattern of a first integrated antenna structure, according to an embodiment.

FIG. 6 illustrates an isometric view of an exemplary second integrated antenna structure, according to an embodiment.

FIG. 7A illustrates a top view of an exemplary second integrated antenna structure, according to an embodiment.

FIG. 7B illustrates a side view of an exemplary second integrated antenna structure, according to an embodiment.

FIG. 8A illustrates the impedance bandwidth response of an exemplary second integrated antenna structure, according to an embodiment.

FIG. 8B illustrates the radiation pattern of an exemplary second integrated antenna structure, according to an embodiment.

FIG. 9 illustrates an exemplary flat panel antenna arrays with a plurality of first integrated antenna structures, according to an embodiment.

FIG. 10 illustrates an exemplary flat panel antenna arrays with a plurality of second integrated antenna structures, according to an embodiment.

FIGS. 11A-11B illustrate an exemplary antenna configuration where one or more integrated antenna structures are connected to radio frequency integrated circuits (RFIC).

DETAILED DESCRIPTION

The present disclosure is here described in detail with reference to embodiments illustrated in the drawings, which form a part here. Other embodiments may be used and/or other changes may be made without departing from the spirit or scope of the present disclosure. The illustrative embodiments described in the detailed description are not meant to be limiting of the subject matter presented here.

Definitions

“Pocket-forming” may refer to generating two or more RF waves which converge in 3-d space, forming controlled constructive and destructive interference patterns.

“Pockets of energy” may refer to areas or regions of space where energy or power may accumulate in the form of constructive interference patterns of RF waves.

“Null-space” may refer to areas or regions of space where pockets of energy do not form because of destructive interference patterns of RF waves.

“Transmitter” may refer to a device, including a chip which may generate two or more RF signals, at least one RF signal being phase shifted and gain adjusted with respect to other RF signals, substantially all of which pass through one or more RF antennas such that focused RF signals are directed to a target.

“Receiver” may refer to a device which may include at least one antenna, at least one rectifying circuit and at least one power converter for powering or charging an electronic device using RF waves.

“Adaptive pocket-forming” may refer to dynamically adjusting pocket-forming to regulate power on one or more targeted receivers.

“Metamaterial” a synthetic composite material with a structure such that it exhibits properties not usually found in natural materials. For example naturally occurring materials normally exhibit a positive refraction index for electromagnetic waves. However, fabricated metamaterials may exhibit a negative refractive index.

“AMC Metamaterial” may refer to an artificial magnetic conductor (AMC) metamaterial that exhibits functionality so that the complex reflection coefficient (S) of a normally incident plane wave, at the material's surface, be S≈1. This makes the total electric field, tangential to the material's surface (which is the sum of the incident and reflected electric fields) to be twice as large as the incident field. In contrast, on common metal surfaces (electric conductors), the total field under these conditions is null. More generally, the material exhibits sufficient AMC bandwidth defined as the frequency band where the real part of the complex reflection coefficient is greater than zero (Re{S}≥0).

“AMC Unit cell” may refer to the parts from which an AMC metamaterial may be composed.

In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, which may not be to scale or to proportion, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings and claims, are not meant to be limiting. Other embodiments may be used and/or other changes may be made without departing from the spirit or scope of the present disclosure.

The present disclosure relates to transmitters, and more specifically, to compact flat panel antenna arrays which may be used for wireless power transmission. The flat panel antenna arrays may include a plurality of integrated antenna structures which may exhibit a directional radiation pattern. Each integrated antenna structures may include a PIFA integrated in an artificial magnetic conductor AMC metamaterial. The AMC metamaterial may provide the antenna with directionality.

Wireless Power Transmission Concept

FIG. 1 illustrates a wireless power transmission 100 using pocket-forming. A transmitter 102 may transmit controlled Radio Frequency (RF) waves 104 which may converge in 3-d space. These RF waves may be controlled through phase and/or relative amplitude adjustments to form constructive and destructive interference patterns. Pockets of energy 106 may form at constructive interference patterns and can be 3-dimensional in shape whereas null-spaces may be generated at destructive interference patterns. A receiver 108 may then utilize pockets of energy 106 produced by pocket-forming for charging or powering an electronic device, for example a laptop computer 110 and thus effectively providing wireless power transmission. In some embodiments, there can be multiple transmitters 102 and/or multiple receivers 108 for powering various electronic devices, for example smartphones, tablets, music players, toys and others at the same time. In other embodiments, adaptive pocket-forming may be used to regulate power on electronic devices.

Components of a Transmitter

FIG. 2 illustrates a component level embodiment for a transmitter 200 which may be utilized to provide wireless power transmission as in wireless power transmission 100. Transmitter 200 may include a housing 202 with at least two or more integrated antenna structures 204, at least one RF integrated circuit (RFIC 206), at least one digital signal processor (DSP) or micro-controller 208, and one communications component 210. Housing 202 can be made of any suitable material which may allow for signal or wave transmission and/or reception, for example plastic or hard rubber. Integrated antenna structures 204 may include suitable antenna types for operating in frequency bands such as 900 MHz, 2.5 GHz or 5.8 GHz as these frequency bands conform to Federal Communications Commission (FCC) regulations part 18 (Industrial, Scientific and Medical equipment). Integrated antenna structures 204 may include vertical or horizontal polarization, right hand or left hand polarization, elliptical polarization, or other suitable polarizations as well as suitable polarization combinations. Suitable antenna types may include, for example, patch antennas with heights from about 1/24 inches to about 1 inch and widths from about 1/24 inches to about 1 inch. Other integrated antenna structures 204 types can be used, for example meta-material antennas, dipole antennas among others. RFIC 206 may include a proprietary chip for adjusting phases and/or relative magnitudes of RF signals which may serve as inputs for integrated antenna structures 204 for controlling pocket-forming. These RF signals may be produced using an external power supply 212 and a local oscillator chip (not shown) using a suitable piezoelectric material. Micro-controller 208 may then process information sent by a receiver through communications component 210 for determining optimum times and locations for pocket-forming. Communications component 210 may be based on standard wireless communication protocols which may include Bluetooth, Wi-Fi, and ZigBee, among others. In addition, communications component 210 may be used to transfer other information such as an identifier for the device or user, battery level, location or other such information. Other communications component 210 may be possible which may include radar, infrared cameras or sound devices for sonic triangulation for determining the device's position.

Integrated Antenna Structures

FIG. 3 illustrates an isometric view of an exemplary first integrated antenna structures 300 that may include the integration of a PIFA 304 with an AMC metamaterial 302 layer for achieving a directional radiation pattern while maintaining a small form factor, according to an embodiment. Specifically, AMC metamaterial 302 may exhibit a configuration of 5×5 arrays of AMC unit cells 326, where these AMC unit cells 326 may include an AMC metal layer 312 and a backing metal layer 314, and may exhibit a square θ ring shape. Additionally, first integrated antenna structures 300 may include a monolithic four layer PCB 306 that may be used as a substrate to suitably integrate AMC metamaterial 302 with PIFA 304. For example, antenna element 308 and folded ground 310 of PIFA 304 may be formed on the top layer of PCB 306; AMC metal layer 312 of AMC metamaterial 302 may be formed in one of the inner layers of PCB 306, and may exhibit a square θ ring shape; backing metal layer 314 of AMC metamaterial 302 may be formed on the other available inner layer of PCB 306; and ground element 316 of PIFA 304 may be formed on the bottom layer of PCB 306.

According to some aspects of this embodiment, folded ground 310 may allow to reduce the dimensions of PIFA 304. PIFA 304 dimensions in the x-axis, y-axis, and z-axis may be about 10 mm, 3.0 mm, and 2.4 mm respectively, for a system area of about 30 mm² and a system volume of about 72 mm³.

A hole 318 may be formed in backing metal layer 314 for allowing signal via 320 and ground via 322 to pass through backing metal layer 314 without electrically shortening it. As a result, ground element 316 of PIFA 304 shorted with backing metal layer 314 may become the primary ground of the first integrated antenna structures 300. At the opposite ends of this primary ground, folded ground vias 324 may short-circuit backing metal layer 314 at a crossing point. In another embodiment where PIFA 304 has no folded ground 310, folded ground vias 324 may be also formed to electrically short backing metal layer 314 and ground element 316.

FIGS. 4A-4B illustrate top and side views of first integrated antenna structures 300. In some embodiments, as illustrated in FIG. 4A, PIFA 304 may occupy about three AMC unit cells 326 of the AMC metamaterial 302 formed on PCB 306. In some embodiments as illustrated in FIG. 4A, first integrated antenna structures 300 may include dimensions of about 18 mm and 18 mm form and n respectively, for a system area of about 324 mm².

FIG. 4B shows a side view of first integrated antenna structures 300 where it may be noticed how the AMC metamaterial 302 is integrated with PIFA 304. As shown in FIG. 4B, antenna element 308 and folded ground 310 may be formed on top side of PCB 306, while ground element 316 may be formed on the bottom side of PCB 306. Backing metal layer 314 and AMC metal layer 312 may be formed in the inner layers of PCB 306, between antenna element 308 and ground element 316. Folded ground vias 324, signal via 320, and ground via 322 are also illustrated in FIG. 4B according to embodiments described herein. Thickness h of first integrated antenna structures 300 may be about 2.4 mm.

Overall dimensions for first integrated antenna structures 300 may vary according to the dimensions used for the AMC metamaterial 302 and PIFA 304, as well as the desired application.

FIG. 5A illustrates the return loss 500 of exemplary first integrated antenna structures 300 when fed by a 50-Ohm port. As shown in FIG. 5A, first integrated antenna structures 300 may exhibit an impedance bandwidth of about 160 MHz at −10 dB, where this bandwidth may provide sufficient margins for possible detuning upon integration of the exemplary first integrated antenna structures 300 into an electronic device or a larger PCB. Radiation efficiency of first integrated antenna structures 300 may be of about 72% at 5.8 GHz.

FIG. 5B illustrates the radiation pattern of first integrated antenna structures 300, where the maximum gain may be of about 2.2 dBi at 5.8 GHz. First integrated antenna structures 300 may exhibit a directional radiation pattern, more specifically, a directional broadside pattern that may be about twice of that of the omnidirectional radiation pattern exhibited by PIFA 304 alone or without the AMC metamaterial 302. In this way, by integrating the AMC metamaterial 302 with PIFA 304 in the first integrated antenna structures 300, the omnidirectional pattern of PIFA 304 may be changed to a directional pattern as exhibited in FIG. 5B, where the AMC metamaterial 302 may operate as an artificial magnetic reflector, sending all the energy upwards. Still, the overall dimensions of first integrated antenna structures 300 may be about 0.345×0.345×0.05 λ³ which may significantly smaller compared to conventional directional antennas such as a patch antennas, half-wave conductor-backed dipole. For example, a half-wave center-fed linear dipole with a quarter-wave backing metal reflector may need a system size of at least 0.5×0.5×0.25 λ³ to achieve a similar performance of first integrated antenna structures 300.

FIG. 6 illustrates an isometric view of an exemplary second integrated antenna structures 600 that may include the integration of PIFA 304 with an AMC metamaterial 602 layer for achieving a directional radiation pattern while maintaining a small form factor, according to an embodiment. More specifically, AMC metamaterial 602 may exhibit a configuration of 6×6 arrays of AMC unit cells 626, where these AMC unit cells 626 may include an AMC metal layer 606 and backing metal layer 314, and may exhibit a square ring shape. Additionally, second integrated antenna structures 600 may include a monolithic four layer PCB 604 that may be used as a substrate to suitably integrate AMC metamaterial 602 with PIFA 304. For example, antenna element 308 and folded ground 310 of PIFA 304 may be formed on the top layer of PCB 604; AMC metal layer 606 of AMC metamaterial 602 may be formed in one of the inner layers of PCB 604 and may exhibit a square shape; backing metal layer 314 of AMC metamaterial 602 may be formed on the other available inner layer of PCB 604; and ground element 316 of PIFA 304 may be formed on the bottom layer of PCB 604.

A hole 608 may be formed in backing metal layer 314 for allowing signal via 320 and ground via 322 to pass through backing metal layer 314 without electrically shortening it. As a result, ground element 316 of PIFA 304 shorted with backing metal layer 314 may become the primary ground of the second integrated antenna structures 600. At the opposite ends of this primary ground, folded ground vias 324 may short-circuit backing metal layer 314 at a crossing point. In another embodiment where PIFA 304 has no folded ground 310, folded ground vias 324 may be configured to electrically short backing metal layer 314 and ground element 316.

FIG. 7A illustrates a top view of second integrated antenna structures 600. In some embodiments, as illustrated in FIG. 7A, PIFA 304 may occupy about eight AMC unit cells 626 of the AMC metamaterial 602 formed on PCB 604. In some embodiments as illustrated in FIG. 7A, second integrated antenna structures 600 may include dimensions of about 18 mm and 18 mm for m and n respectively, for a system area of about 324 mm².

FIG. 7B shows a side view of second integrated antenna structures 600 where it may be noticed how the AMC metamaterial 602 is integrated with PIFA 304. As shown in FIG. 7B, antenna element 308 and folded ground 310 may be formed on top side of PCB 604, while ground element 316 may be formed on the bottom side of PCB 604. Backing metal layer 314 and AMC metal layer 606 may be formed in the inner layers of PCB 604, between antenna element 308 and ground element 316. Folded ground vias 324, signal via 320, and ground via 322 are also illustrated in FIG. 7B according to embodiments described herein. Thickness h of second integrated antenna structures 600 may be about 2.4 mm.

Overall dimensions for second integrated antenna structures 600 may vary according to the dimensions used for the AMC metamaterial 602 and PIFA 304, as well as the desired application.

FIG. 8A illustrates the return loss 800 of exemplary second integrated antenna structures 600 when fed by a 50-Ohm port. As shown in FIG. 8A, second integrated antenna structures 600 may exhibit an impedance bandwidth of about 160 MHz at −10 dB, where this bandwidth may provide sufficient margins for possible detuning upon integration of the exemplary second integrated antenna structures 600 into an electronic device or a larger PCB. Radiation efficiency of second integrated antenna structures 600 may be of about 67% at 5.8 GHz.

FIG. 8B illustrates the radiation pattern of second integrated antenna structures 600, where the maximum gain may be of about 2.0 dBi at 5.8 GHz. Second integrated antenna structures 600 may exhibit a directional radiation pattern, more specifically a directional broadside pattern that may be about twice of that of the omnidirectional radiation pattern exhibited by PIFA 304 alone or without the AMC metamaterial 602. In this way, by integrating the AMC metamaterial 602 with PIFA 304 in the second integrated antenna structures 600, the omnidirectional pattern of PIFA 304 may be changed to a directional pattern as exhibited in FIG. 8B, where the AMC metamaterial 602 may operate as an artificial magnetic reflector, sending all the energy upwards. Still, the overall dimensions of second integrated antenna structures 600 may be about 0.345×0.345×0.05 λ³ which may significantly smaller compared to conventional directional antennas such as patch antennas, and half-wave conductor-backed dipoles. For example, a half-wave center-fed linear dipole with a quarter-wave backing metal reflector may need a system size of at least 0.5×0.5×0.25 to achieve a similar performance of second integrated antenna structures 600.

Given the compact form factors and the suitable directional radiation patterns exhibited by first integrated antenna structures 300 and second integrated antenna structures 600, they can be used in antenna arrays that may be included in transmitter 200 for wireless power transmission as described in the following embodiments.

FIG. 9 illustrates an exemplary embodiment of a first flat panel antenna arrays 900 that may include a plurality of first integrated antenna structures 300, where this flat panel antenna arrays 900 can be used in transmitter 200 for sending focused RF waves towards a receiver for wireless power charging or powering, according to an embodiment.

Flat panel antenna arrays 900 may include an N number of first integrated antenna structures 300 distributed in an equally spaced grid. In one embodiment, flat panel antenna arrays 900 may exhibit dimensions on the X and Y axis of about 16 inches and 14 inches respectively. First integrated antenna structures 300 formed on flat panel antenna arrays 900 may exhibit spacing h and w of about 1/10 λ to about 1/15 λ. This reduced spacing between first integrated antenna structures 300 may be due to their high directionality. As a result, first integrated antenna structures 300 can be placed very close together without or minimum coupling, thereby allowing a high density of first integrated antenna structures 300 in flat panel antenna arrays 900. In one embodiment, flat panel antenna arrays 900 may fit about 418 first integrated antenna structures 300.

Each first integrated antenna structures 300 in flat panel antenna arrays 900 may be operated independently, thus enabling an enhanced control over the pocket forming. For example, by individually controlling each first integrated antenna structures 300, the gain and phase of each first integrated antenna structures 300 can be adjusted for obtaining a narrower RF beam, and thereby allowing a higher coherent gain for flat panel antenna arrays 900. In addition, the higher number of first integrated antenna structures 300 may contribute to a higher gain for flat panel antenna arrays 900.

In general, the number of first integrated antenna structures 300 in flat panel antenna arrays 900 may vary in relation with the desired range and power transmission capability for transmitter 200. Additionally, the spacing between each first integrated antenna structures 300 on flat panel antenna arrays 900 may vary as well. Alternate configurations for flat panel antenna arrays 900 may be considered, including circular patterns or polygon arrangements. Flat panel antenna arrays 900 may also be broken into numerous pieces and distributed across multiple surfaces (multi-faceted). Shape and orientation of first integrated antenna structures 300 may vary in dependency of the desired features of transmitter 200, as well as various orientation types and combinations in three dimensional arrangements. Additionally, the AMC metamaterial 302 in first integrated antenna structures 300 may allow radio signal transmission with high efficiency, good heat dissipation and the like.

Moreover, first integrated antenna structures 300 in flat panel antenna arrays 900 may operate in frequency bands, such as 900 MHz, 2.5 GHz or 5.8 GHz as these frequency bands conform to Federal Communications Commission (FCC) regulations part 18 (Industrial, Scientific and Medical equipment). First integrated antenna structures 300 may also operate in independent frequencies, allowing a multichannel operation of pocket-forming.

In other embodiments, shielding (not shown in FIG. 9) may be applied between first integrated antenna structures 300 in flat panel antenna arrays 900 to eliminate or further reduce coupling.

FIG. 10 illustrates an exemplary embodiment of a first flat panel antenna arrays 1000 that may include a plurality of second integrated antenna structures 600, where this flat panel antenna arrays 1000 can be used in transmitter 200 for sending focused RF waves towards a receiver for wireless power charging or powering, according to an embodiment.

Flat panel antenna arrays 1000 may include an N number of second integrated antenna structures 600 distributed in an equally spaced grid. In one embodiment, flat panel antenna arrays 1000 may exhibit dimensions on the X and Y axis of about 16 inches and 14 inches respectively. Second integrated antenna structures 600 formed on flat panel antenna arrays 1000 may exhibit spacing h and w of about 1/10 λ to about 1/15 λ. This reduced spacing between second integrated antenna structures 600 may be due to their high directionality. As a result, second integrated antenna structures 600 can be placed very close together without or minimum coupling, thereby allowing a high density of second integrated antenna structures 600 in flat panel antenna arrays 1000. In one embodiment, flat panel antenna arrays 1000 may fit about 418 second integrated antenna structures 600.

Each second integrated antenna structures 600 in flat panel antenna arrays 1000 may be operated independently, thus enabling an enhanced control over the pocket forming. For example, by individually controlling each second integrated antenna structures 600, the gain and phase of each second integrated antenna structures 600 can be adjusted for obtaining a narrower RF beam, and thereby allowing a higher coherent gain for flat panel antenna arrays 1000. In addition, the higher number of second integrated antenna structures 600 may contribute to a higher gain for flat panel antenna arrays 1000.

In general, the number of second integrated antenna structures 600 in flat panel antenna arrays 1000 may vary in relation with the desired range and power transmission capability for transmitter 200. Additionally, the spacing between each second integrated antenna structures 600 on flat panel antenna arrays 1000 may vary as well. Alternate configurations for flat panel antenna arrays 1000 may be considered, including circular patterns or polygon arrangements. Flat panel antenna arrays 1000 may also be broken into numerous pieces and distributed across multiple surfaces (multi-faceted). Shape and orientation of second integrated antenna structures 600 may vary in dependency of the desired features of transmitter 200, as well as various orientation types and combinations in three dimensional arrangements. Additionally, the AMC metamaterial 602 in second integrated antenna structures 600 may allow radio signal transmission with high efficiency, good heat dissipation and the like.

Moreover, second integrated antenna structures 600 in flat panel antenna arrays 1000 may operate in frequency bands, such as 900 MHz, 2.5 GHz or 5.8 GHz as these frequency bands conform to Federal Communications Commission (FCC) regulations part 18 (Industrial, Scientific and Medical equipment). Second integrated antenna structures 600 may also operate in independent frequencies, allowing a multichannel operation of pocket-forming.

In other embodiments, shielding (not shown in FIG. 10) may be applied between second integrated antenna structures 600 in flat panel antenna arrays 1000 to eliminate or further reduce coupling.

FIGS. 11A-11B illustrate an isometric view of exemplary antenna arrangement configurations 1100 where one or more integrated antenna structures 204 may be connected to at least one RFIC 206. In one embodiment, a flat transmitter 200 may include a plurality of integrated antenna structures 204, such as first integrated antenna structures 300 or second integrated antenna structures 600, connected to one or more RFIC 206 in a flat panel antenna arrays 1200 configuration.

For example, FIG. 11A, illustrates a subset of 4 integrated antenna structures 204, that may be connected to a single RFIC 206.

In another embodiment, a row or column of integrated antenna structures 204 may be connected to a single RFIC 206, as shown in FIG. 11B.

In a further embodiment, 2 integrated antenna structures 204 (not shown in FIGS. 11A-11B) may be connected to a single RFIC 206 and this in turn to a single RFIC 206, which may be connected to a final RFIC 206 and this in turn to one or more micro-controller 208. Furthermore, a higher reliability and accuracy may be achieved because multiple redundancy of RFIC 206.

In another embodiment, RFIC 206 may be directly embedded behind each integrated antenna structures 204 (not shown in FIGS. 11A-11B); such integration may reduce losses due the shorter distance between components. Specifically, in flat panel antenna arrays 1200, the phase and the amplitude of each pocket-forming in each integrated antenna structures 204 may be regulated by the corresponding RFIC 206 in order to generate the desired pocket-forming and null steering. RFIC 206 singled coupled to each integrated antenna structures 204 may reduce processing requirement and may increase control over pocket-forming, allowing multiple pocket-forming and a higher granular pocket-forming with less load over micro-controller 208; thus, a higher response of higher number of multiple pocket-forming may be allowed. Furthermore, multiple pocket-forming may charge a higher number of receivers and may allow a better trajectory to such receivers.

In conclusion, integrated antenna structures 204 may operate in single array, pair array, quad array, or any other suitable arrangement, which may be designed in accordance with the desired application. As described in FIG. 11A, RFIC 206 may be coupled to one or more micro-controllers 208. Furthermore, micro-controllers 208 may be included into an independent base station or into flat transmitter 200.

While various aspects and embodiments have been disclosed herein, other aspects and embodiments are contemplated. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims. 

What is claimed is:
 1. An antenna for transmitting focused radio-frequency (RF) waves towards a receiver to provide wireless power thereto, the antenna comprising: an integrated antenna structure, wherein the integrated antenna structure: is on a multi-layer printed circuit board (PCB); includes a first group of unit cells with a planar inverted F-antenna (PIFA) transmitting element and a second group of unit cells without a transmitting element, and each respective unit cell of the first and second groups of unit cells is made of an artificial magnetic conductor (AMC) material, wherein: a ground element of the PIFA transmitting element is formed in a bottom layer of the multi-layer printed circuit board and the PIFA transmitting element is formed on a top layer of the multi-layer PCB, a metal layer associated with the AMC material is formed on a first inner layer of the multi-layer PCB that is between the top and bottom layers, and a backing metal layer associated with the AMC material is formed on a second inner layer of the multi-layer PCB that is between the top and bottom layers; and is configured to transmit, via the transmitting element, RF wireless power waves having a wavelength (λ) to a wireless power receiver, and wherein the second group of unit cells without the transmitting element surrounds at least four sides of the first group of unit cells on the multi-layer printed circuit board and is configured to reflect at least some of the RF wireless power towards the wireless power receiver.
 2. The antenna of claim 1, wherein: the transmitting element included in the first group of unit cells is configured to transmit the RF wireless power waves in an omnidirectional fashion, and reflection of the at least some of the RF wireless power waves by the second group of unit cells causes the integrated antenna structure to directionally transmit the RF wireless power waves towards the wireless power receiver.
 3. The antenna of claim 1, wherein the first and the second groups of unit cells are arranged in an array.
 4. The antenna of claim 1, wherein the PIFA also has a folded ground element formed on the top layer of the multi-layer PCB.
 5. The antenna of claim 1, wherein: a respective signal via passes through the backing metal layer, the respective signal via configured to provide the RF wireless power waves to the antenna element of the PIFA, and a respective ground via passes through the backing metal layer to provide a ground path for the PIFA.
 6. The antenna of claim 1, wherein the integrated antenna structure is configured to operate in a frequency band of an RF spectrum, wherein the band is selected from a group consisting of 900 MHz, 2.5 GHz, and 5.8 GHz.
 7. The antenna of claim 1, further comprising a radio frequency integrated circuit (RFIC) coupled to the integrated antenna structure, the RFIC configured to control generation of the RF wireless power waves. 